I got a smoking deal on a gun safe today but it is not fire rated. I have heard people say that many gun safes are lined with sheetrock for fire resistance but I can not find any details on this. Anybody know if there is a certain type to use or just regular old sheetrock from home depot and how much it takes for a decent degree of protection? I was thinking I could line it with 2 layers of half inch rock pretty easily. Also, any idea where to get the kind of door seal that swells up in a fire to keep the smoke out?